There has been a running debate over the past 18 years as to whether psychoapthy is a “taxon”; “an entity, type, syndrome, disease, or more generally, a nonarbitrary class.” The concept goes back to Paul Meehl (1982; 1995) who laid out the importance of the concept for classifying psychopathology. Harris, Rice and Quinsey (1994) argued that psychopathy is a taxon, based on certain PCL-R Factor 2 items as well as childhood conduct disorder variables (which they incoporated in both the VRAG and SOARG, commonly used violence risk measures). The issue of categories vs. dimensions is a major issue in contemporary personality theory and assessment (should personality traits be considered discrete categories or as dimensional?), including current debates on revising the DSM 5, Axis 2 models of personality disorders. Generally, evidence of a psychopathy taxon has been weak in the literature (see Edens, et al, 2006). In their latest paper, Harris, Rice, et al., 2007, identify a “psychopathic sexuality taxon,” and conclude that coercive and precocious sexuality is a fundamental aspect of psychopathy. In response, Walters, G., and his colleagues (2011) published a strong response, based on taxometric research, that psychopathy is a dimensional construct. They argue against “reifying the existence of discrete psychopathological entities when the phenomenon in question in fact has dimensional underlying structure.”
The whole series of paper is a fascinating survey of competing models in psychopathology, personality assessment, and psychopathy with associated policy and public safety isses (see previous post on the Skeem et al (2010) psychopathy monograph).
Sources: Edens, J., Marcus, D. et al, (2006). Psychopathic, not psychopath: Taxometric evidence for the dimensional structure of psychopathy. Journal of Abnormal Psychology, 115, 1, 131–144.
Meehl, P. & Golden, (1982). Taxometric methods. In Butcher, J., et al. Handbook of research methods in clinical psychology.
Meehl, P. (1995). Bootstrap taxometrics. Solving the classification problem in psychopathology. American Psychologist, 50(4), 266–275.
Harris, Rice, & Quinsey (1994). Psychopathy as a taxon: Evidence that psychopaths are a discrete class. JCCP, 62,2, 387–397.
Harris, G., Hilton, et al ( 2007). Coercive and precocious sexuality as a fundamental aspect of psychopathy. Journal of Personality Disorders, 21, 1, 1–27.
Walters, G., et al . (2011). In search of the psychopathic sexuality taxon? Indicator size does matter. Behavioral Sciences and the Law, 29, 23–29.